Flexible fluorine-containing material having heat resistance and non-tackiness

ABSTRACT

To provide the fluorine-containing material which is capable of giving various products, particularly products and parts for OA equipment, is excellent in flexibility, mechanical strength, viscoelasticity and mold-processability and possesses improved non-tackiness. The flexible fluorine-containing material comprises (a) the fluorine-containing multi-segment polymer having the elastomeric fluorine-containing polymer chain segment A and the non-elastomeric fluorine-containing polymer chain segment B in which the elastomeric fluorine-containing polymer chain segment A comprises not less than 90% by mole of a perhaloolefin unit and (b) the fluorine-containing resin having a crystalline melting point or glass transition temperature of not less than 150° C., in which a weight ratio (a)/(b) is 1/99 to 99/1.

TECHNICAL FIELD

The present invention relates to a fluorine-containing material havingheat resistance and non-tackiness while having flexibility.

BACKGROUND ART

Fluorine-containing materials such as fluorine-containing resins andfluorine-containing rubbers are used as various starting materials invarious fields by utilizing specific properties thereof Particularly thefluorine-containing materials play an important role in the field of OAequipment.

In that field, hitherto a urethane rubber, EP rubber, silicone rubberand the like have been used for rolls for printing machine and platenrolls. Also a silicone rubber roll, a fluorine-containing rubber rolland the like are known as a fuser roll for electro photographic copyingmachine. However in those rolls, even in case of use of a toner havingreleasing property, since releasing property (non-tackiness againsttoner) is not enough, a non-elastic roll coated with afluorine-containing resin, an elastic roll covered with a shrinkablefluorine-containing resin tube on its surface, or the like has beenproposed. Further there have been proposed an elastic roll obtained bycoating a mixture of fluorine-containing rubber and fluorine-containingresin powder and then baking to form a fluorine-containing resin powderlayer on the surface of roll (JP-B-1-36622), a roll obtained by coatinga fluorine-containing rubber and fluorine-containing resin powder,baking and then further coating a fluorine-containing resin powder toform a fluorine-containing resin layer PJP-B-6-100876), and the likeroll.

In fixing operation of electrophotographic copying machine, coating of areleasing oil, generally a silicone oil on a fuser roll is carried outto improve releasing property of the fuser roll. In that case, in orderto prevent a silicone oil from permeating inside the fuser roll andcausing swelling of the roll, there have been proposed a fuser rollobtained by covering a shrinkable fluorine-containing resin tube on anelastic roll or a fuser roll provided with a silicone rubber layer, afluorine-containing rubber layer or a fluorosilicone rubber layer and asilicone rubber layer in that order on its metallic core roll asdescribed in JP-A- 1-205188, etc.

Also in JP-A-62-285839, the inventors of the present invention proposedan elastic roll obtained by forming, on its metallic core roll, a layerof a heat resistant elastomer material impregnated and integrated withfibrillated polytetrafluoroethylene (PTFE), particularly stretchedporous polytetrafluoroethylene.

On the other hand, in the roll for printing machine and platen rollwhich are produced by using a urethane rubber, EP rubber or siliconerubber, elasticity of the roll is good, but releasing property cannotalways be said to be good. For that reason, there were problems thattroubles such as adherence of toner, contamination of printed mattersdue to adherence of paper powder and winding of paper on a rolloccurred.

Particularly in case of the fuser roll for electrophotographic copyingmachine, a non-elastic roll coated with a fluorine-containing resin suchas PFE or PFA (copolymer of tetrafluoroethylene and perfluoro(alkylvinyl ether)) has a defect that the roll has no elasticity, and a rollobtained by covering a surface of elastic roll with a shrinkablefluorine-containing resin tube is not always satisfactory from theviewpoint of surface elasticity since the fluorine-containing resin ishard and small in elongation. Further an elastic roll having afluorine-containing resin powder layer on its surface (formed by powdercoating of PFA, etc.) is good in elasticity and releasing property at aninitial stage of its use, but since the fluorine-containing resin powderon its surface is easily peeled or separated, a life of the releasingproperty is short and further in application for a fuser roll in whichits temperature becomes as high as 150° to 200° C., heat resistance ofthe roll is not enough. Particularly since the fluorine-containingrubber component is deteriorated and strength thereof is decreased,durability of the roll is lowered.

Also as described in JP-A-1-205188, etc., with respect to the rollhaving a silicone rubber layer on a fluorine-containing rubber layer orfluorosilicone rubber layer, strength of the silicone rubber layer onthe roll surface is insufficient. If an amount of a filler is increasedto increase the strength, releasing property is lowered. Further sincean adhesive strength between the silicone rubber layer and thefluorine-containing rubber layer or fluorosilicone rubber layer is notenough, there is a problem that coating of a silicone oil and fixingoperations are carried out repeatedly, thereby causing cracking on thesurface silicone rubber layer and peeling thereof in the worst case.Further in application for a fuser roll in which its temperature becomesas high as 150° to 200° C., the surface silicone rubber layer and theinside fluorine-containing rubber layer or fluorosilicone rubber layerare deteriorated and abraded due to lowering of strength since heatresistance thereof is insufficient.

Also the elastic roll disclosed in JP-A-62-285839 is very excellent inreleasing property and good in affinity and anti-swelling property witha silicone oil, but is poor in elastic properties, particularlyelasticity recovering ability. Further the elastic roll is poor in heatconductivity and has a problem that its surface temperature is loweredparticularly at the time of copying continuously.

In recent years, in a copying machine, the tendency is toward colorprinting and higher copying speed, and thus a surface material for rollsof fixing part which has more flexibility, heat resistance andnon-tackiness is demanded.

In LBP having a tendency toward color printing, high quality image andhigh speed, a toner itself also has a tendency of multi-colors and lowviscosity. From the viewpoint of prevention of offsetting, morenon-tackiness is also demanded on a material to be used on a surface ofthe fuser roll.

An object of the present invention is to provide a flexiblefluorine-containing material which can cope with the above-mentionedproblems in the field of OA equipment and naturally can be applied onvarious products, parts and coating in other fields.

The present inventors have found that a specific fluorine-containingmulti-segment polymer having an elastomeric fluorine-containing polymerchain segment capable of giving flexibility to the whole polymer and anon-elastomeric fluorine-containing polymer chain segment is suitablefor applications where heat resistance, flexibility and non-tackinessare demanded, and also have found that the above-mentioned problematicpoints can be further improved by a combination of the specificfluorine-containing multi-segment polymer and a specificfluorine-containing resin.

The flexible fluorine-containing material can be preferably usedparticularly as a material for rolls of OA equipment to be used forelectronically fixing and photo-sensing applications. Particularly byusing on a fuser roll, excellent fixing property, color developingproperty, oil resistance, non-tackiness against toner and releasabilityof a paper can be exhibited and further heat resistance, non-tackiness,durability and abrasion resistance can be given to the surface of theroll.

DISCLOSURE OF INVENTION

The present invention relates to a flexible fluorine-containing materialwhich comprises (a) a fluorine-containing multi-segment polymer havingan elastomeric fluorine-containing polymer chain segment A and anon-elastomeric fluorine-containing polymer chain segment B in which theelastomeric fluorine-containing polymer chain segment A comprises notless than 90% by mole of perhaloolefin units and (b) afluorine-containing resin having a crystalline melting point or glasstransition temperature of not less than 150° C., in which a weight ratio(a)/(b) is 1/99 to 99/1.

It is preferable that the elastomeric fluorine-containing polymer chainsegment A contained in the fluorine-containing multi-segment polymer (a)is non-crystalline and has a glass transition temperature of not morethan 25° C. and that the elastomeric fluorine-containing polymer chainsegment A is a polymer chain comprising 50 to 85% by mole oftetrafluoroethylene and 15 to 50% by mole of perfluoro(alkyl vinylether) and/or hexafluoropropylene.

It is preferable that the non-elastomeric fluorine-containing polymerchain segment B contained in the fluorine-containing multi-segmentpolymer (a) is a polymer chain having a crystalline melting point orglass transition temperature of not less than 150° C., particularly notless than 250° C. and that the non-elastomeric fluorine-containingpolymer chain segment B is, a polymer chain comprising more than 85% bymole and not more than 100% by mole of tetrafluoroethylene and 0% bymole or less than 15% by mole of a compound of the formula (1):

CF₂═CF—R_(f) ¹  (1)

wherein R_(f) ¹ is CF₃ or OR_(f) ², in which R_(f) ² is a perfluoroalkylgroup having 1 to 5 carbon atoms.

Particularly it is preferable that a proportion of the non-elastomericfluorine-containing polymer chain segment B contained in thefluorine-containing multi-segment polymer (a) is not more than 25% byweight based on the whole segment polymer (a).

On the other hand, it is preferable that the above-mentionedfluorine-containing resin (b) is a fluorine-containing resin having acrystalline melting point or glass transition temperature of not lessthan 250° C. and further that the fluorine-containing resin (b) is oneor more members selected from perfluoro fluorine-containing resins,particularly polytetrafluoroethylene (PTFE),tetrafluoroethylene/perfluoro(alkyl vinyl ether) copolymer (PFA),tetrafluoroethylene/hexafluoropropylene copolymer (FEP) andtetrafluoroethylene/hexafluoropropylene/perfluoro(alkyl vinyl ether)copolymer (EPA).

The preferable weight ratio (a)/(b) is 40/60 to 99/1.

BEST MODE FOR CARRYING OUT THE INVENTION

First the fluorine-containing multi-segment polymer which is thecomponent (a) of the present invention is explained below.

It is important that the fluorine-containing multi-segment polymercontains, in one molecule thereof, the elastomeric fluorine-containingpolymer chain segment A (hereinafter referred to as “elastomeric segmentA”) and the non-elastomeric fluorine-containing polymer chain segment B(hereinafter referred to as “non-elastomeric segment B”) which arebonded in a blocked or grafted form.

In the present invention, for bonding the elastomeric segment A to thenon-elastomeric segment B by blocking or grafting to obtain thefluorine-containing multi-segment polymer, various known processes can-be adopted. Among them, a process for preparing a blockedfluorine-containing multi-segment polymer which is disclosed inJP-B-58-4728, etc., a process for preparing a graftedfluorine-containing multi-segment polymer which is disclosed inJP-A-62-34324, and the like process can be adopted preferably.

Particularly preferred is the blocked fluorine-containing multi-segmentpolymer synthesized through a so-called iodine transferringpolymerization method which is disclosed in JP-B-58-4728 and KobunshiRonbunshu (Vol. 49, No. 10, 1992) from the viewpoint that a segmentingratio (blocking ratio) is high and a uniform and regular segment polymercan be obtained.

On the other hand, in case of a simple mixture of an elastomericfluorine-containing polymer and non-elastomeric fluorine-containingpolymer, generally mechanical properties (particularly at hightemperature) become insufficient and lowering of abrasion resistance,flexibility and durability arises though it depends on kind, miscibilityand compatibility of the respective polymers to be mixed.

On the contrary, when the fluorine-containing resin is mixed to themulti-segment polymer prepared by bonding the elastomeric segment A andthe non-elastomeric segment B by blocking or grafting like the presentinvention, heat resistance, mechanical properties (particularly at hightemperature), etc. are enhanced more and also in case of use for rolls,heat resistance, durability and abrasion resistance can be improved moreeffectively as compared with the above-mentioned simple mixture of anelastomeric fluorine-containing polymer and non-elastomericfluorine-containing polymer.

Further a rubber roll provided with a layer of fluorine-containingthermoplastic rubber having an elastomeric fluorine-containing polymerchain segment containing vinylidene fluoride as a main component on itsouter surface has been proposed (Utility Model PublicationJU-B-2-15873). However though the fluorine-containing segment polymer isused, heat resistance and non-tackiness are not enough because theelastomeric fluorine-containing polymer chain segment does not contain aperhaloolefin unit as a main component.

The present inventors have further found that in the iodine transferringpolymerization method, when not less than 90% by mole of perhaloolefinunits are contained as a recurring unit in the elastomeric segment A, ablock copolymerization reaction with a monomer for the non-elastomericsegment B proceeds regularly and uniformly and it is possible to largelydecrease an amount of unintended products such as a molecule comprisingonly the elastomeric fluorine-containing polymer chain segment which isnot bonded to the non-elastomeric component and the non-elastomericfluorine-containing polymer chain segment having a low molecular weighteven if a bonding occurs. The inventors also have found that theflexible fluorine-containing material of the present invention producedby mixing the thus obtained fluorine-containing multi-segment polymer(a) to the fluorine-containing resin (b) is excellent in mechanicalproperties, heat resistance, mechanical properties at high temperatureand abrasion resistance and molded article produced therefrom is usefulas a material for various products, for example, a heat resistantmaterial for OA equipment, particularly rolls and belts for OAequipment. On the other hand a material comprising an unintendedfluorine-containing multi-segment polymer having an un-reactedelastomeric fluorine-containing polymer chain segment has an adverseeffect on products and parts produced therefrom such as lowering ofmechanical strength, heat resistance and abrasion resistance.

Further the present inventors have found that by mixing thefluorine-containing multi-segment polymer (a) to the fluorine-containingresin (b), non-tackiness, particularly easiness of removing a stain isexcellent as compared with a mere blend of an elastomericfluorine-containing polymer and a fluorine-containing resin and amaterial comprising only a fluorine-containing multi-segment polymer.

The flexible fluorine-containing material of the present invention canbe given a good flexibility by the elastomeric segment A contained inthe fluorine-containing multi-segment polymer (a) to be used.Particularly when using for rolls and belts for OA equipment, it ispreferable that an elastic modulus of the whole flexiblefluorine-containing material is not more than 7×10⁸ dyn/cm² at 150° C.,particularly not more than 5×10⁸ dyn/cm² at 150° C., thereby giving agood fixing property and color developing property even in applicationsfor fuser rolls or belts, in which the tendency is toward high qualitypicture and coloring.

Examples of the usable perhaloolefin as a recurring unit of theelastomeric segment A arc, for instance, tetrafluoroethylene (TFE),chlorotrifluoroethylene (CTFE), perfluorovinylethers such asperfluoro(alkyl vinyl ether) (alkyl group has 1 to 5 carbon atoms)(PAVE) and

CF₂═CFO(CF₂CFYO_(p)—CF₂CF₂CF₂O )_(q)R_(f)

wherein Y is F or CF₃, R_(f) is a perfluoroalkyl group having 1 to 5carbon atoms, p is 0 or an integer of from 1 to 5, q is 0 or an integerof from 1 to 5, provided that p+q≧1, hexafluoropropylene (HFP), and thelike. Among them, those having a combination and composition givingelastomeric property can be used. Further a monomer giving a curing sitefor peroxide crosslinking, polyol crosslinking, polyamine crosslinkingand other curing reaction and a monomer having functional group forimparting adhesive property, etc. with other material may be introducedin an amount of not more than 10% by mole.

In the fluorine-containing multi-segment polymer (a) to be used in thepresent invention, the elastomeric segment A is a segment which isgenerally non-crystalline and has a glass transition temperature of notmore than 25° C. Examples of the preferred composition thereof are, forinstance, 50 to 85/15 to 50/0 to 10% by mole, particularly 50 to 80/20to 50/0 to 5% by mole of TFE/PAVE/monomer giving a curing or adheringfunction.

Examples of the monomer giving a curing site are, for instance,vinylidene fluoride, CF₂═CHI, iodine-containing monomers represented byCX₂═CX—R_(f) ³CHRI, in which X is H, F or CH₃, R_(f) ³ is a linear orbranched fluoro- or perfluoro-alkylene group or fluoro- orperfluoro-oxyalkylene group which may have at least one ether typeoxygen atom, a fluoropolyoxyalkylene group or a perfluoropolyoxyalkylenegroup, R is H or CH₃, nitrile-containing monomers represented by:

wherein m is from 0 to 5, n is from 1 to 3,

wherein n is from 1 to 4,

CF₂═CFO(CF₂_(n)—OCF(CF₃)X⁴,

wherein n is from 2 to 5,

wherein n is from 1 to 6,

CF₂═CF[OCF₂CF(CF₃)]_(n)OCF₂CF(CF₃)X⁴,

wherein n is from 1 to 2, and

wherein X⁴ is CN, COOH or COOR¹, in which R¹ is an alkyl group which has1 to 10 carbon atoms and may contain fluorine atom, bromine-containingmonomers, carboxyl group containing monomers, alkoxycarbonylgroup-containing monomers, and the like. Usually the iodine-containingmonomer, nitrile-containing monomer, carboxyl group-containing monomer,or the like is suitable.

A suitable iodine-containing monomer is a perfluoro(vinyl ether)compound from the viewpoint of its copolymerizability. For example,perfluoro(6,6 dihydro-6-iodo-3-oxa-1-hexene) andperfluoro(5-iodo-3-oxa-1-pentene) are suitable.

Other examples are fluorovinylethers described in JP-B-5-63482 which arerepresented by the formula:

ICH₂CF₂CF₂(OCFY³CF₂_(n)—OCF═CF₂,

wherein Y³ is a trifluoromethyl group, n is 0 or an integer of 1 to 2,and the like.

Examples of the monomer capable of giving good adhesion to othermaterials, e.g. metals such as aluminum and stainless steel and organicmaterials such as silicone rubber and polyimide, arenon-fluorine-containing or fluorine-containing monomers having hydroxylgroup, carboxyl group, carboxylic acid derivative, sulfonic acid,sulfonic acid derivative, epoxy group, acetyl group or the like.

In order to impart enough flexibility to rolls for OA equipment,particularly a fuser roll and a soft roll of pressure roll, it ispreferable that the glass transition temperature of the elastomericsegment A in the fluorine-containing multi-segment polymer of thepresent invention is not more than 10° C.

The elastomeric segment A can be prepared by iodine transferringpolymerization method known as a process for preparing afluorine-containing rubber (JP-B-58-4728, JP-A-62-12734).

For example, there is a method of carrying out emulsion polymerizationwith stirring the above-mentioned perhaloolefin and if necessary, amonomer giving a curing site under pressure in water mediumsubstantially under oxygen-free condition in the presence of an iodinecompound, preferably a diiodine compound and a radical polymerizationinitiator.

Representative examples of the diiodine compound to be used are, forinstance, 1-3-diiodoperfluoropropane, 1,4-diiodoperluorobutane,1,3-diiodo-2-chloroperfluoropropane,1,5-diiodo-2,4-dichloroperfluoropentane, 1,6-diiodoperfluorohexane,1,8-diiodoperfluorooctane, 1,12-diiodoperfluorododecane,1,16-diiodoperfluorohexadecane, diiodomethane and 1,2-diiodoethane Thosecompounds can be used alone or in a mixture thereof. Among them,1,4-diiodoperfluorobutane is preferred. An amount of the diiodinecompound is from 0.01 to 1% by weight based on the total weight of theelastomeric segment A.

A radical polymerization initiator which is used for preparing theelastomeric segment A of the present invention may be the same as thatwhich has been used for polymerization of a fluorine-containingelastomer. Examples thereof are organic and inorganic peroxides andazo-compounds. Representative examples of the initiator are persulfates,carbonate peroxides, peroxide esters, and the like. Preferred initiatoris ammonium persulfate (APS). The APS can be used alone or incombination with a reducing agent such as sulfites.

Though a wide range of emulsifying agents can be used for the emulsionpolymerization, from a point of inhibiting a chain transfer reactionwith the molecules of the emulsifying agent which occurs during thepolymerization, carboxylic acid salts having a fluorocarbon chain orfluoropolyether chain are desirable. An amount of the emulsifying agentis desirably from about 0.05 to about 2% by weight, particularlydesirably from 0.2 to 1.5% by weight based on added water.

Since the monomer mixture gas used in the present invention is explosiveas described in Advances in Chemistry Series, G. H. Kalb et al, 129, 13(1973), it is necessary to take measures for a polymerization equipmentnot to cause a sparking. From that point of view, it is preferable thata polymerization pressure is as low as possible.

The polymerization pressure can be changed in a wide range, generally ina range of from 0.5 to 5 MPa. The higher the polymerization pressure is,the more a polymerization speed increases. Therefore the polymerizationpressure is desirably not less than 0.8 MPa from the viewpoint ofincreasing productivity.

It is preferable that a number average molecular weight of the thusobtained elastomeric segment A is from 5,000 to 750,000, particularlyfrom 20,000 to 400,000 from the viewpoint of imparting flexibility,elasticity and mechanical properties to the whole fluorine-containingmulti-segment polymer obtained.

An end of the thus obtained elastomeric segment A is of perhalo tppe andhas an iodine atom which becomes a starting point of blockcopolymerization of the non-elastomeric segment B.

In the present invention, the non-elastomeric segment B is basically notlimited if it has a fluorine atom and does not have the above-mentionedelastomeric property. The non-elastomeric segment B may be selectedaccording to characteristics and functions which are intended to beobtained by block-copolymerizing the non-elastomeric segment B.

Among the monomers constituting the non-elastomeric. segment B, examplesof the fluorine-containing monomer are, for instance, one or more ofperhaloolefins such as TFE, CTFE, PAVE, HFP, CF₂═CF(CF₂)_(p)X³ in whichp is an integer of from 1 to 10, X³ is F or Cl, and perfluoro-2-butene;and partly fluorinated olefins such as vinylidene fluoride (VdF), vinylfluoride, trifluoroethylene,

CH₂═CX¹—CF₂_(q)—X²

in which X¹ and X² are H or F, q is an integer of from 1 to 10, andCH₂═C(CF₃)₂. Also one or more of monomers copolymerizable therewith, forexample, ethylene, propylene, vinyl chloride, vinyl ethers, vinyl estersof carboxylic acid and acryls can be used as copolymerizable components.

Among them, from the viewpoint of chemical resistance and heatresistance, a sole use of fluorine-containing olefin, a combination offluorine-containing olefins, a combination of ethylene and TFE and acombination of ethylene and CTFE are preferable as the monomers to beused as the main components. Particularly a sole use of perhaloolefinand the combination of perhaloolefins are preferable.

Examples thereof are

(1) VdF/TFE (0 to 100/100 to 0), particularly VdF/TFE (70 to 99/30 to1), TFE or PVdF;

(2) ethylene/TFE/HFP (6 to 43/40 to 81/10 to 30),3,3,3-trifluoropropylene-1,2-trifluoromethyl-3,3,3-trifluoropropylene-1/PAVE (40 to 60/60 to 40);

(3) TFE/CF₂═CF—R_(f) ¹ (amount exhibiting non-elastomeric property,namely, an amount of CF₂═CF—R_(f) ¹ is less than 15% by mole. R_(f) ¹ isCF₃ or OR_(f) ², in which R_(f) ² is a perfluoro alkyl group having 1 to5 carbon atoms);

(4) VdF/TFE/CTFE (50 to 99/30 to 0/20 to 1);

(5) VdF/TFE/HFP (60 to 99/30 to 0/10 to 1);

(6) ethylene/TFE (30 to 60/70 to 40);

(7) polychlorotrifluoroethylene (PCTFE);

(8) ethylenc/CTFE (30 to 60/70 to 40); and the like.

When heat resistance and abrasion resistance are required in case of amaterial for fuser rolls and belts in the field of OA equipment, it ispreferable that a crystalline melting point of the non-elastomericsegment B is not less than 150° C. In case of a material for fuser rollsand belts particularly for high speed copying machine or printer, thecrystalline melting point is particularly preferably not less than 250°C. Particularly from the viewpoint of good heat resistance,non-tackiness and abrasion resistance, the non-elastomericfluorine-containing polymer chain segment having perhaloolefin as a mainrecurring unit is preferred.

Further it is particularly preferable that the non-elastomeric segment Bin the fluorine-containing multi-segment polymer of the presentinvention is the polymer chain comprising more than 85% by mole and notmore than 100% by mole of tetrafluoroethylene and 0% by mole or lessthan 15% by mole of the formula (1) represented by:

CF₂═CF—R_(f) ¹  (1)

wherein R_(f) ¹ is CF₃ or OR_(f) ², in which R_(f) ² is a perfluoroalkylgroup having 1 to 5 carbon atoms. The resulting polymer exhibitsexcellent characteristics such as heat resistance, abrasion resistanceand non-tackiness against toner in case of use for rolls for OAequipment and fuser rolls.

An iodine atom at a molecular end of the fluorine-containingmulti-segment polymer of the present invention can be replaced withanother atom or organic group by various methods.

For example, the molecular end of the fluorine-containing multi-segmentpolymer of the present invention consisting of perhaloolefin can befluorinated and replaced with —CF₃ group by treating the polymer with afluorine gas.

Thereby non-tackiness, heat resistance, oil resistance and chemicalresistance of the fluorine-containing multi-segment polymer can beenhanced more.

The treatment with fluorine gas is carried out by bringing thefluorine-containing multi-segment polymer of the present inventionconsisting of perhaloolefin into contact with a fluorine gas usually at50° to 250° C., preferably at a temperature up to 200° C. for 1 to 10hours, preferably for 2 to 5 hours. A treating pressure may be from 1 to10 kgG/cm², usually an atmospheric pressure. The fluorine gas to be usedmay be a pure fluorine gas. From the viewpoint of safety, the fluorinegas diluted with an inert gas such as nitrogen gas, helium gas or argongas to 2 to 25% by volume, preferably 7 to 15% by volume is preferred.

When brought into contact with the fluorine gas, the fluorine-containingmulti-segment polymer (a) may be in any form of powder, pellet or flake.The polymer can be subjected to fluorination treatment after formed intoa film, tube or other molded article.

To the non-elastomeric segment B or to the structure of thefluorine-containing multi-segment polymer (a) of the present invention,if necessary, a carboxyl group or its derivative, hydroxyl group,sulfonic acid group or its derivative, epoxy group or the like can beintroduced by copolymerization of a monomer having functional group orby reaction of an end group of the segment polymer, and thereby adhesionto a substrate, crosslinkability and affinity for a filler can beenhanced and various other functions can be imparted.

Block copolymerization of the non-elastomeric segment B can be carriedout subsequently to the emulsion polymerization of the elastomericsegment A by changing a monomer to one for the non-elastomeric segmentB.

A number average molecular weight of the non-elastomeric segment B canbe adjusted in a wide range of from 1,000 to 1,200,000, preferably from3,000 to 600,000. An important feature of the present invention is touse the fluorine-containing multi-segment polymer in which thenon-elastomeric segment B can be securely block-copolymerized with theelastomeric segment A and the molecular weight (degree ofpolymerization) of the non-elastomeric segment B can be increased. Asmentioned above, this can be achieved by making the elastomeric segmentA have perhaloolefin units of not less than 90% by mole, particularlynot less than 95% by mole as a recurring unit.

The thus obtained fluorine-containing multi-segment polymer (a) mainlycomprises polymer molecules (B—A—B) in which the non-elastomericsegments B are bonded to both sides of the elastomeric segment A andpolymer molecules (A—B) in which the non-elastomeric segment B is bondedto one side of the elastomeric segment A. An amount of polymer molecules(C) which comprise only the elastomeric segment A without being bondedto the non-elastomeric segment B is not more than 20% by weight,preferably not more than 10% by weight based on the total amount of thesegment A and polymer molecule (C) in the fluorine-containingmulti-segment polymer.

When the polymer having the polymer molecule (C) in an amount exceeding20% by weight is mixed to the fluorine-containing resin (b), mechanicalproperties and abrasion resistance of products and parts producedtherefrom are lowered. Particularly in case of use for a roll and beltfor OA equipment which are heated to 150° C. or more, an abrasionresistance particularly at high temperature is lowered.

The proportion of the elastomeric segment A and the non-elastomericsegment B in the fluorine-containing multi-segment polymer (a) of thepresent invention is optionally selected depending on kind of intendedproducts and parts, for example, rolls and belts for OA equipment,required properties, etc. and also depending on the compositions of eachsegment. The proportion of the elastomeric segment A to thenon-elastomeric segment B is preferably selected in the range of from5:95 to 99:1 (% by weight). Particularly in case of use as a materialfor rolls at fixing part where flexibility, heat resistance and abrasionresistance are required, the proportion of the elastomeric segment A tothe non-elastomeric segment B is preferably from 20:80 to 98:2 (% byweight), further preferably from 50:50 to 98:2 (% by weight).

Also in case of use, for example, for rolls and belts of OA equipment,if the proportion of the elastomeric segment A is too small, flexibilitybecomes insufficient and fixing property and color developing propertybecome insufficient. If the proportion of the non-elastomeric segment Bis too small, there is a tendency that heat resistance, mechanicalproperties at use at high temperatures and abrasion resistance becomeinsufficient. When the proportion of the non-elastomeric segment B isnot more than 30% by weight from the viewpoint of mold-processability,the segment polymer (a) having excellent mold-processability,particularly melt-moldability, melt-extrusion moldability and injectionmoldability can be provided. Particularly since the melt-extrusionmoldability is excellent, a film or tube having a thickness of as thinas about 10 μm to about 500 μm and a smooth surface can be produced.From this point of view, it is further preferable that the proportion ofthe segment A to the segment B is from 70:30 to 98:2 (% by weight).

When a crosslinking point is provided by introducing a curing site inthe elastomeric segment A, vulcanization (crosslinking) can be carriedout by peroxide vulcanization with known organic peroxides, polyolvulcanization with known polyols, polyamine vulcanization with knownpolyvalent amine compounds, and the like.

Also the vulcanization can be carried out by a method of triazinecrosslinking by forming a triazine ring with an organotin compound (forexample, JP-A-58-152041), a method of oxazole crosslinking by forming anoxazole ring with bisaminophenol similarly by using afluorine-containing elastomer having a nitrile group introduced as acrosslinking point (for example, JP-A-59-109546), a method of imidazolecrosslinking by forming an imidazole ring with a tetraamine compound(for example, JP-A-59-109546) and a method of thiazole crosslinking byforming a thiazole ring with bisaminothiophenol (for example,JP-A-8-104789), or the like method.

Next, the fluorine-containing resin as the component (b) is explainedbelow. The fluorine-containing resin (b) is naturally a substancedifferent from the above-mentioned fluorine-containing multi-segmentpolymer (a).

The fluorine-containing resin (b) has a crystalline melting point orglass transition temperature of not less than 1 50° C. and possesses anability of improving heat resistance and particularly mechanicalproperties at high temperatures without lowering the excellentnon-tackiness and mechanical properties of the fluorine-containingmulti-segment polymer (a).

The fluorine-containing resin is selected from those mentioned abovedepending on purpose and application of the flexible material of thepresent invention. When the flexible material is used as a surfacematerial and molding material such as rolls of OA-related equipment,sealing materials for automotive-related parts and sealing materials forsemiconductor producing equipment, the crystalline melting point orglass transition temperature thereof is not less than 150° C., morepreferably not less than 250° C.

Among the fluorine-containing resins, perfluoro fluorine-containingresins having excellent heat resistance, non-tackiness, chemicalresistance and friction property and capable of giving such propertiesto the flexible fluorine-containing material, particularly one or moreof PTFE, PFA, FEP and EPA are preferable.

In the flexible fluorine-containing material of the present invention,the preferable weight ratio (a)/(b) of the component (a) to thecomponent (b) can be selected in a wide range of from 1/99 to 99/1.Particularly in order to maintain flexibility sufficiently and providemechanical properties and heat resistance, the weight ratio is 20/80 ormore, particularly 30/70 or more, 40/60 to 99/1, 50/50 to 90/10,particularly 80/20 or less.

A combination of the fluorine-containing multi-segment polymer (a) andthe fluorine-containing resin (b) is optionally selected. Particularly aselection of the fluorine-containing resin (b) having the same orsimilar components as those of the non-elastomeric segment B in thefluorine-containing multi-segment polymer (a) is preferable from theviewpoint of excellent compatibility between the both components.

For example, the following combinations are preferable.

A Composition Comprising:

(a) Fluorine-containing multi-segment polymer

Segment A: TFE/PAVE (PAVE: 30 to 50% by mole) copolymer

Segment B: TFE/PAVE (PAVE: 0.5 to 5% by mole) copolymer

(b) Fluorine-containing resin PFA,

A Composition Comprising:

(a) Fluorine-containing multi-segment polymer

Segment A: TFE/PAVE copolymer

Segment B: TFE/HFP copolymer

(b) Fluorine-containing resin FEP,

A Composition Comprising:

(a) Fluorine-containing multi-segment polymer

Segment A: TFE/PAVE copolymer

Segment B: TFE homopolymer

(b) Fluorine-containing resin

A resin selected from PTFE, PFA, FEP and EPA, and

A Composition Comprising:

(a) Fluorine-containing multi-segment polymer

Segment A: TFE/PAVE copolymer

Segment B: TFE/HFP/PAVE copolymer

(b) Fluorine-containing resin

A resin selected from EPA, PFA and FEP.

In case of the composition mainly comprising, for example, thefluorine-containing multi-segment polymer (a) and thefluorine-containing resin (b) (for example, PTFE or PTFE copolymer)which cannot be melt-molded, mixing thereof may be carried out by usualmethod of mixing PTFE containing a filler. The flexiblefluorine-containing material of the present invention can be obtained bymixing with a mixer, for example, a tumbler mixer, Henschel mixer, orthe like and is used as a molding material for compression molding, etc.In case of the composition mainly comprising the fluorine-containingmulti-segment polymer (a) and the fluorine-containing resin (b) (forexample, PFA, FEP, EPA, or the like) which are melt-moldable,melt-mixing is preferable. Examples of the melt-mixing equipment are amixing roll, Banbury mixer, Brabender mixer, extruder and the like.Among them, the extruder is preferable from the points that a kneadingpower is larger and enhancement of a dispersibility can be expected moreat blending the fluorine-containing multi-segment polymer (a) and thefluorine-containing resin (b) and that a productivity for producing thematerial is good. For mixing, the extruder having a single screw or twoor more screws can be used, and particularly a two-screw extruder ispreferred because a kneading power is large, thereby making it possibleto obtain a composition having a good dispersibility and a kneadingpower can be controlled optionally.

The composition is generally formed into a pellet by the melt-mixing andis used as a molding material for melt-extrusion molding into a tube orfilm and injection molding. Further the composition is pulverized andcan be used as a coating material.

To the flexible fluorine-containing material of the present inventioncan be mixed various fillers depending on purpose and applications.

Particularly when the flexible fluorine-containing material of thepresent invention is used as a material for rolls and belts of OAequipment which are represented by fuser rolls of a copying machine,printer, etc., fillers which can impart electric conductivity to theroll surface are mixed mainly.

Examples of the filler for imparting electric conductivity are carbonblacks (Ketjen Black, Acetylene Black, etc.); carbons such as PAN typecarbon fiber, pitch type carbon fiber and pulverized expansive graphite;fluorinated carbons obtained by completely or partly fluorinating thosecarbons; metals such as Ag, Ni, Cu, brass, silver-plated copper, Zn, Aland stainless steel (in the form of powder, flake, fiber or the like);metal oxides in the form of fine particles such as SnO₂ (Sb dope), In₂O₃(Sn dope) and ZnO (Al dope); ferrites; highly dielectric substances suchas barium titanate; and the like.

An adding amount of the filler capable of imparting electricconductivity is optionally selected depending on a desired surfaceresistance or volume specific resistance of rolls or belts for OAequipment and further depending on kind of an electrically conductivefiller to be used. The adding amount is from about 0.1 to 40% by weight,preferably from 1 to 30% by weight based on the whole compositioncomprising the flexible fluorine-containing material of the presentinvention and the filler.

Particularly a partly fluorinated carbon is preferred from the. pointsthat the resistance can be controlled stably in a narrow range of from,10⁸ to 10¹³ Ωcm and that electric conductivity can be given withoutlowering non-tackiness of the fluorine-containing polymer.

Examples of the preferred partly fluorinated carbon are those obtainedby fluorinating carbon materials such as carbon black, carbon fiber,petroleum coke and graphite powder.

Among them, preferred is a fluorinated carbon black obtained byfluorinating carbon black, particularly a fluorinated carbon blackhaving a ratio F/C of fluorine atom to carbon atom of not less than 0.1and less than 1.0, particularly not less than 0.1 and less than 0.5.

If the F/C of the fluorinated carbon black is less than 0.1, an effectof the fluorination is insufficient and problems which a carbon materialbefore the fluorination possesses remain unsolved, namely a problem thata ratio of change in resistance for an adding amount is very large andcontrolling of electric conductivity is difficult and a problem thatdispersing of fluorinated carbon black becomes non-uniform due to adeveloped structure and the obtained composition becomes hard. If theF/C is not less than 1.0, a desired electric conductivity cannot begiven to the composition.

The F/C is measured by the method mentioned below. The fluorinatedcarbon black is wrapped together with a combustion improver Na₂O₂ and apolyethylene film with a filtrating paper, and burnt in a tightly closedflask filled with oxygen. Hydrogen fluoride generated is measured by ausual method by using a fluoride ion meter (Ion Analyzer 901 availablefrom Orion Co., Ltd.). A fluorine content is calculated from theobtained value. Then the F/C is calculated from the obtained fluorinecontent.

The fluorinated carbon black mainly comprises a poly(carbonmonofluoride). Preferred is a fluorinated carbon black obtained byfluorinating a carbon black having an average particle size of from 0.01to 50 μm, preferably from 0.01 to 1 μm with a fluorine gas. In case of afluorinated carbon black obtained by using a carbon material having anaverage particle size exceeding 50 μm, for example, petroleum coke,graphite powder, carbon fiber, or the like as a starting material, anadding amount thereof has to be increased for imparting electricconductivity and non-tackiness to the resin, and disadvantages tend toarise, such as an increase in a surface roughness of the obtainedcomposition, lowering of mechanical strength and non-uniform resistance.

The carbon materials suitable for the fluorinated carbon black arecarbon blacks having an average article size in the above-mentionedrange. Carbon blacks which can be used are those commercially available,for example, Furnace Black for rubber (for example, ASAHI #55 availablefrom Asahi Carbon Co., Ltd., etc.), Channel Black for coloring (forexample, LEBEN 7000 available from Columbia Carbon Co., Ltd.), ThermalBlack (SEVACARBON MT-C1 available from Columbia Carbon Co., Ltd.), andthe like.

Among the carbon blacks, particularly those generally called anelectrically conductive carbon black are preferred. The electricallyconductive carbon blacks are those defined by factors such as a smalleraverage particle size (not more than 0.1 μm), a large surface area (N₂surface area: 50 m²/g or more), a developed structure (oil absorption:100 cc/g or more), a less content of impurities (ash content: less than0.1%) and an advanced graphitization, and are widely used because even arelatively small amount thereof can impart electric conductivity to thematerial. Examples of the commercially available electrically conductivecarbon black are, for instance, Ketjen Black EC and Ketjen BlackEC-600JD (available from Ketjen Black International Co., Ltd.), BlackPearls 2000, Vulcan XC-72 and CSX-99 (available from Cablack Co., Ltd.),Denca Black (available from Denki Kagaku Kogyo Kabushiki Kaisha),Conductex 950 (available from Columbia Carbon Co., Ltd.), and the like.

The fluorinated carbon black can be obtained by contacting theabove-mentioned carbon materials with a fluorine gas at a temperaturewithin a range of from 200° to 600° C., preferably from 300° to 500° C.In a reaction temperature range lower than the mentioned i range, thereoccur the problems that a progress of the fluorination reaction is slow,a degree of the fluorination is hardly increased, a thermal stability isnot sufficient and the properties inherent to the fluorinated carbonblack such as non-tackiness and lubricity are not exhibited. On thecontrary, in a reaction temperature range higher than the mentionedrange, a thermal cracking reaction easily arises and a yield of anobtained fluorinated carbon black is decreased. Also there is a casewhere a sudden thermal cracking occurs, resulting in an explosion.Therefore attention must be paid to that.

The fluorine gas to be used for the reaction may be diluted with aninert gas such as nitrogen, argon, helium, carbon tetrafluoride, or thelike or may contain hydrogen fluoride. The reaction can be carried outunder normal pressure, and even if the reaction is carried out underreduced pressure or under pressure, there is no problem.

Besides the above-mentioned conditions, a reaction time, a fluorine gasflow, etc. may be optionally adjusted depending on a reactivity of thestarting carbon material with fluorine and a desired F/C value (fluorinecontent).

The proportion of the fluorine-containing multi-segment polymer of thepresent invention to the fluorinated carbon is optionally selecteddepending on a desired resistance, and is from 1/99 to 20/80 (weightratio, hereinafter the same). If an amount of the fluorinated carbonblack becomes small, an effect of the addition thereof is notsufficiently obtained, and if the amount becomes too large, there is atendency that a mechanical strength such as a tensile strength islowered.

Further a filler for enhancing mechanical properties and compressionrestoration property may be mixed to the composition. Typical examplesof the preferable filler are fibrous fillers such as a glass fiber,carbon fiber, asbestos fiber and potassium titanate fiber.

Examples of rolls for OA equipment, to which the flexiblefluorine-containing material of the present invention having heatresistance and non-tackiness is applied, are as follows.

Roll Example 1

(i) Metallic core roll of aluminum or stainless steel

(ii) Fluorine-containing material of the present invention whichcomprises 40 to 99% by weight of the fluorine-containing multi-segmentpolymer (a) comprising, as the elastomeric segment A, not less than 75%by weight of one or more segments comprising a polymer chain having amolecular weight of 5,000 to 750,000 and obtained by copolymerizing 50to 85% by mole of tetrafluoroethylene with 15 to 50% by mole ofperfluoro(alkyl vinyl ether) and as the non-elastomeric segment B, 25%by weight of one or more segments comprising a polymer chain having amolecular weight of 3,000 to 1,200,000 and obtained by polymerizing morethan 85% by mole and not more than 100% by mole of tetrafluoroethylenewith 0% by mole or less than 15% by mole of the formula (1):

CF₂═CF—R_(f) ¹  (1)

wherein R_(f) ¹ is CF₃ or —OR_(f) ², in which R_(f) ² is aperfluoroalkyl group having 1 to 5 carbon atoms, and 1 to 60% by weightof the fluorine-containing resin (b), preferably a perfluoro polymerhaving a crystalline melting point or glass transition temperature ofnot less than 150° C. Fuser roll or pressure roll at a fixing part whichis produced by laminating (ii) as an outer layer of (i).

Roll Example 2

(i) Metallic core roll of aluminum or stainless steel

(ii) Composition prepared by mixing a filler capable of impartingelectric conductivity to the fluorine-containing multi-segment polymerdescribed in (ii) (outer layer) of Roll Example 1 Fuser roll or pressureroll at a fixing part which is produced by laminating (ii) as an outerlayer of (i).

The fluorine-containing material of the present invention itself hasflexibility and therefore even if laminated directly on the metalliccore roll as described in the above-mentioned Roll Examples 1 and 2,enough flexibility can be obtained. In addition, by providing an elasticlayer of silicone rubber, fluorine-containing rubber, urethane rubber,EPDM or the like, the roll can be endowed with more flexibility andeffectively comply with requirements for higher quality picture andpaper feeding property at high speed. Among them, the elastic layershaving a rubber hardness of 10 to 40 degrees or not more than 10 degrees(including a layer in the form of sponge) are selected.

Roll Example 3

(i) Metallic core roll of aluminum or stainless steel

(ii) Silicone rubber

(iii) Flexible fluorine-containing material described in (ii) (outerlayer) of Roll Example 1

Fuser roll or pressure roll at a fixing part which is produced bylaminating the silicone rubber layer (ii) on the core roll (i) andthereon the layer (iii) as an outermost layer.

Roll Example 4

(i) Metallic core roll of aluminum or stainless steel

(ii) Silicone rubber

(iii) Composition prepared by mixing a filler capable of impartingelectric conductivity to the fluorine-containing material described in(ii) (outer layer) of Roll Example 1

Fuser roll or pressure roll at a fixing part which is produced bylaminating the silicone rubber layer (ii) on the core roll (i) andthereon the layer (iii) as an outermost layer.

Between each layer of each layered roll of the above-mentioned RollExamples 1 to 4, an adhesive or primer may be used to improve adhesionthereof.

Preferred are Roll Examples 3 and 4. Usually any one of the fuser rollor pressure roll of the fixing part or the both of them are providedwith a heating device such as a ceramic heater to soften or melt a tonerfor fixing an image to a paper. The material of the present inventionhas enough heat resistance against such a heating device.

The flexible fluorine-containing material of the present invention isused as a molding material which can be molded into the form of sheet,film or tube and thus is applied on the roll or belt for OA equipment.In that case, known molding methods can be used. The fluorine-containingmulti-segment polymer or the composition prepared by blending a fillerto the fluorine-containing multi-segment polymer can be molded intonecessary forms by extrusion molding, injection molding, compressionmolding or the like.

Further the flexible fluorine-containing material of the presentinvention can be used as a coating material when prepared into acomposition containing a liquid carrier or into a powder form having aspecific particle size and apparent density. The coating material can beused not only for application in OA equipment but also for a liningmaterial, roll, belt, hose, sealing material, and the like in the fieldsof transportation such as automobiles, semiconductor productionfacilities, chemical plant, aircraft, food processing facilities,photographic and printing facilities, coating apparatuses, steel makingfacilities, etc. The coating material comprises the above-mentionedfluorine-containing multi-segment polymer (a) and thefluorine-containing resin (b). As the fluorine-containing multi-segmentpolymer (a) and the fluorine-containing resin (b), those described abovein the heat resistant material for OA equipment having flexibility canbe preferably used similarly. The coating material is applied on therolls and belts for OA equipment and substrates in other applicationsand a coating film having excellent flexibility, sealing property, heatresistance, abrasion resistance and non-tackiness can be obtained.

Further the flexible fluorine-containing material of the presentinvention can be applied on the coating powder. For the coating powder,the same material as the above-mentioned heat resistant material for OAequipment having flexibility can be preferably used. The coating powderwhich is used preferably is in the form of powder or particle having aparticle size of from 10 to 1,000 μm and an apparent density of from 0.3to 1.2 g/cc.

To the coating powder can be optionally added additives, for example, apigment such as a carbon powder, titanium oxide or cobalt oxide; areinforcing material such as a glass fiber powder, carbon fiber powderor mica; an amine type anti-oxidant, organic sulfuric compound,organotin type anti-oxidant, phenolic anti-oxidant or a thermalstabilizer such as metal soap; a leveling agent; an anti-static agent;the same filler as mentioned above which is capable of impartingelectric conductivity; and the like in the range not lowering remarkablycharacteristics of the fluorine-containing resin such as heatresistance.

Mixing of the coating powder to the above-mentioned additives may becarried out in the form of powder (dry type) or in the form of slurry(wet type). Preferred is the mixing in the form of powder. Examples ofthe usable mixing equipment are, for instance, usual mixers such as asand mill, V-type blender and ribbon type blender and pulverizingmachine.

The coating powder is generally coated through electrostatic coating,fluid bed dipping, rotary lining or the like and then baked (preferablyat a temperature of not less than a crystalline melting point thereof)to form a good coating film.

Generally it is possible to form a coating film of from 10 to 200 μmthick in case of the electrostatic powder coating and from 200 to 1,000μm thick in case of the rotary lining.

The flexible fluorine-containing material of the present invention canbe formed into a coating composition by mixing to a liquid medium. Forthe coating composition, the same flexible fluorine-containing materialsas those for the above-mentioned heat resistant material for OAequipment having flexibility can be preferably used.

The liquid carrier to be used for the coating composition is selectedfrom liquids which can dissolve or disperse the fluorine-containingmulti-segment polymer (a) and the fluorine-containing resin (b)constituting the flexible fluorine-containing material of the presentinvention. Examples thereof are alcohols such as methanol, ethanol,propanol and butanol and in addition, hydrocarbon type solvents such asacetone, methyl ethyl ketone, ethyl acetate, dimethylformamide,dimethylacetamide, N-methyl-2-pyrrolidone, dimethylsulfoxide,triethylphosphate, tetrahydrofuran, methyl isobutyl ketone,cyclohexanone, 1,4-dioxane, methyl cellosolve acetate, 2-nitropropane,methyl isoamyl ketone, 4-methoxy-4-methylpentanone-2 and4-methoxy-4-methylpentanol-2; haloalkanes such astrichlorotrifluoroethane, dichlorotetrafluoroethane,dichlorodifluoroethane, chlorodifluoroethane,dichloropentafluoropropane, tetrachlorohexafluorobutane andperfluorohexane; fluorine-containing solvents such asfluorine-containing ethers, i.e. FLORINATE FC-75 (available from Three MCo., Ltd.), FLORINATE FC-77 (available from Three M Co., Ltd.) andHFE7100 (available from Three M Co., Ltd.); water; and a mixture of twoor more thereof.

Also it is possible to blend usual additives such as a pigment,surfactant, anti-foaming agent, viscosity control agent and levelingagent in the range not lowering remarkably heat resistance, chemicalresistance, non-tackiness and abrasion resistance.

Besides the additives, a coupling agent can be used as another componentto enhance adhesive property.

The coupling agent means a compound which acts on an interface betweenthe organic material and the inorganic material and forms a strongbridge between the both materials through chemical or physical coupling.The coupling agent is usually a compound of silicone, titanium,zirconium, hafnium, trium, tin, aluminum or magnesium which has a groupcapable of coupling the organic material and the inorganic material.Among those coupling agents, preferred are a silane coupling agent,ortho-acid esters of transition elements (for example, titanium orzirconium) of the group IV in Periodic Table and derivatives thereof,and particularly preferred is an amino silane compound.

The coating composition can be in the form of aqueous dispersion,organic solvent dispersion, organosol or aqueous emulsion of organosolcontaining the flexible fluorine-containing material of the presentinvention and if necessary, the above-mentioned additives. Among them,the form of aqueous dispersion for a coating is preferred fromenvironmental and safety point of view. Particularly preferred is thecomposition in the state of the fluorine-containing multi-segmentpolymer being dispersed in water in the form of fine particles of from0.01 to 1.0 μm, in which a surfactant is generally blended forstabilizing the dispersion.

The aqueous dispersion for a coating can be prepared through variousprocesses. Concretely there are, for example, a process for finelypulverizing a powder of fluorine-containing multi-segment polymerobtained by suspension polymerization, or the like, mixing the finelypulverized powder to the fluorine-containing resin powder and thendispersing the mixture uniformly in an aqueous medium with a surfactant,a process for preparing an aqueous dispersion of fluorine-containingmulti-segment polymer at the same time of polymerization by emulsionpolymerization, mixing, thereto, the fluorine-containing resin finepowder or an aqueous dispersion of fluorine-containing resin obtained byemulsion polymerization and if necessary, adding a surfactant andadditives, and the like process. From the viewpoint of productivity andquality (for forming into smaller and uniform particle size), theprocess for preparing the aqueous dispersions of both thefluorine-containing multi-segment polymer (a) and thefluorine-containing resin (b) directly through the emulsionpolymerization and then mixing the both dispersions is preferred.

A method of coating of the coating composition is optionally selecteddepending on kind of the fluorine-containing multi-segment polymer, formof a coating, purpose and application. For example, in case of theaqueous dispersion and organic solvent dispersion, usually spraycoating, brush coating, roll coating and spin coating are carried out.After the coating, drying and sintering are carried out to give acoating film on a substrate. The sintering conditions are optionallyselected depending on kind (composition, melting point, etc.) of thefluorine-containing multi-segment polymer (a) and thefluorine-containing resin (b). Generally the sintering is carried out ata temperature of not less than the melting point of the non-elastomericsegment B in the fluorine-containing multi-segment polymer (a) and notless than the melting point of the fluorine-containing resin (b). Thesintering time is from five minutes to three hours, preferably fromabout 10 minutes to about 30 minutes while it varies depending on thesintering temperature.

Such a coating material is coated on a metallic core roll (aluminum andSUS) of a roll as a heat resistant material for OA equipment havingflexibility in the same manner as mentioned above or on an elastic layerof silicone rubber, fluorine-containing rubber, urethane rubber or EPDMprovided on the core roll, and thus a fuser roll or pressure roll havingnot only flexibility, heat resistance and abrasion resistance but alsoexcellent non-tackiness and oil resistance can be obtained.

In order to obtain the above-mentioned rolls for OA equipment byapplying the coating material, after applying, if necessary, a primer tothe metallic core roll or intermediate elastic layer and then sinteringdepending on necessity, it is possible to coat any of the aqueousdispersion coating, solvent-soluble coating, solvent-dispersion coatingor powder coating comprising the coating material of the presentinvention by the above-mentioned method and then sinter at a temperatureof not less than a melting point thereof to form a coating film. Thethickness of the coating film varies depending on purpose, applicationand hardness of a substrate, and is selected in the range of from 1 to500 μm, preferably from 5 to 150 μm, particularly from 5 to 100 μm. Ifnecessary, the coating film may be ground to make its surface smooth. Itis preferable to adjust a surface roughness (Ra) to not more than 2.0μm, more preferably not more than 1.0 μm.

Also there is another method of producing rolls for OA equipment, thatis, a method of producing a tube from the flexible fluorine-containingmaterial of the present invention and covering a metallic core roll withthe obtained tube. The tube is a cylindrical article obtained by moldingthe flexible fluorine-containing material into a tubular form. Theabove-exemplified flexible fluorine-containing material can bepreferably used similarly.

A size of the tube varies depending on purpose, application and methodof use, and is not limited. There is usually used a tube having an innerdiameter of about 5 to 50 mm and a thickness of not more than 1 mm.Particularly in case of rolls for OA equipment such as fuser rolls andpressure rolls, the inner diameter and thickness are preferably from 10to 40 mm and from 0.01 to 0.15 μm, respectively.

The tube is formed into a tube by usual melt-extrusion. The tube may bestretched (single screw or two screws) if necessary and may have thermalshrinkability, but usually may have neither stretchability nor thermalshrinkability.

The tube may contain the above-mentioned filler imparting electricconductivity if necessary. The tube can be produced usually by mixingpreviously an electric conductivity-imparting agent by kneading or dryblending to the starting material (in the form of pellet or powder)before molding into the tube by melt-extrusion.

The molding method is also not limited particularly. Generally meltextrusion molding with a ring die is carried out as mentioned above.Namely a cylindrical film melt-extruded through a ring die with a singlescrew or multi-screw extruder is taken off while being cooled as it iswith a proper cooling means or is taken off while adjusting its size andshape toward inside or outside by using a sizing jig after the ring dieand cooling at normal temperature or with a coolant such as air orwater. In that case, there is no restriction in employing suchconditions as feeding of air into the cylindrical article, stretchingsomewhat at the time of taking off and carrying out slow cooling orrapid cooling.

The tube usually comprises one layer, and may comprise two or morelayers. In such a case, it is necessary to study enough and selectcompatibility between polymers of each layer and a heating temperatureunder specific conditions mentioned below. This is because a heattreating temperature of each layer differs from each other. Molding iscarried out by co-extrusion method, and there are no specific conditionslike the molding of one layer.

The tube is optionally subjected to inner surface treatment, ifnecessary, in order to enhance adhesion to an article to be covered withthe tube. Example of the preferred inner surface treatment is chemicaletching treatment, and for example, sodium-based etching agent is usedpreferably. In addition to the chemical etching, any of inner surfacetreatments may be employed as far as enhancement of adhesion can beexpected. Further after the chemical etching of the inner surface, aprimer may be applied to enhance adhesion to a substrate more.

The tube produced by using the material of the present invention is usedfor rolls (particularly for fuser roll and pressure roll) for OAequipment and can impart excellent flexibility and heat resistance tothe rolls. In addition to those characteristics, good non-tackiness canbe given by fitting the tube on an outermost surface of the roll.

The roll provided with the tube may be produced as mentioned above bycovering its metallic core roll directly with the tube or by providingan elastic layer of silicone rubber, fluorine-containing rubber,urethane rubber or EPDM between the metallic core roll and the tube.

While the tube can impart enough flexibility to the roll surface even ifcovered directly on the metallic core roll, more flexibility can begiven to the roll surface by providing the elastic layer between thecore roll and the tube, and in case of use as a fuser roll and pressureroll for OA equipment, a higher quality picture and enhanced paperfeeding property at high speed can be attained. In that case, an elasticlayer having a rubber hardness of from about 10 degrees to about 30degrees or an elastic layer having a rubber hardness of not more than 10degrees (including a layer in the form of sponge) is preferred.

If necessary, an adhesive is used or treatment with a primer is carriedout to impart adhesion between the tube and the substrate (metallic coreroll or elastic layer) contacting thereto. In that case, it ispreferable to use the above-mentioned tube subjected to the innersurface treatment by etching from the point that a stronger adhesion canbe obtained.

In producing the roll by providing the tube directly on the metalliccore roll, known methods can be optionally employed. It is preferablethat a tube having thermal shrinkability and subjected to etchingtreatment of its inner surface is covered on a metallic core rollsubjected to primer treatment and is shrunk at a temperature of not morethan a melting point (for example, at 150° to 200° C.) for setting tothe substrate, followed by sintering at a temperature of not less thanthe melting point (for example, at 320° to 400° C.) to bond by fusion.

The roll having an elastic layer between the tube and the metallic coreroll can be produced by a method of firstly putting the metallic coreroll and the tube in a cylindrical molded article so that a space isprovided between the core roll and the tube and the inner surface of thecylindrical molded article comes into contact with the outer surface ofthe tube, and then pouring a raw rubber, latex or elastomer into theabove-mentioned space, and if necessary carrying out vulcanizing. It isa matter of course that the roll covered with the tube has to be takenout of the cylindrical molded article at a necessary time. In that case,the inner surface of the tube may be previously subjected to etchingtreatment or primer treatment so that it is easily contacted to therubber portion. Also a rubber roll may be produced previously and thencovered with the tube on the surface of the rubber roll. In that case,it is better to use a tube having thermal shrinkability. Thus there isno restriction in the production method of the roll.

When the roll obtained above is used as rolls for OA equipment such as afuser roll and pressure roll, a step for making the surface of rollsmooth may be carried out as the case demands.

For example, a surface roughness (Ra) of the roll can be decreased bygrinding the roll surface. Preferred Ra is not more than 2 μm, morepreferably not more than 1.0 μm.

Further the flexible fluorine-containing material of the presentinvention can be used in various applications other than the applicationfor OA equipment, by making use of its heat resistance, chemicalresistance, non-tackiness, flexibility, sealing property and abrasionresistance. Examples of the application are shown in Tables 1, 2 and 3.

TABLE 1 Field of Sub-field industry of industry Final product EquipmentElectrical Semi- Semi-conductor CVD equipment conductor productionapparatus Liquid crystal panel Dry etching production apparatusequipment Plasma panel Wet etching production apparatus equipmentOxidation and diffusion equipment Sputtering equipment Ashing equipmentCleaning equipment Ion implantation equipment Transportation Vehicle CarEngine and auxiliary equipment AT Fuel line and auxiliary equipmentAircraft Aircraft Fuel line Rocket Rocket Fuel line Ship Ship Fuel lineParts ◯ (square) ring, packing, sealing material, tube, roll Coating,lining, gasket, diaphragm, hose Gasket, shaft seal, valve stem seal,sealing material, hose Hose, sealing material ◯ (square) ring, tube,packing, core material of valve, hose, sealing material, diaphragmDiaphragm, ◯ (square) ring, valve, tube, packing, hose, sealing materialDiaphragm, ◯ (square) ring, valve, tube, packing, hose, sealing materialDiaphragm, ◯ (square) ring, valve, tube, packing, hose, sealing materialChemical Chemical Plant Production line of products chemicals such aspharmaceutical, agricultural chemical, coating and resin (Petroleum)Chemicals Pharmaceuticals Plug for chemicals Mechanical Photo-Developing machine Film developing graph machine X-ray film developingPrinting Printing machine Printing roll Coating Coating facilitiesCoating roll Analyzer and physical and chemical appliances Food PlantFood processing line Metal Steel Steel sheet Steel sheet makingprocessing facilities processing roll Lining, valve, packing, roll,hose, diaphragm, ◯ (square) ring, tube, sealing material Plug forchemicals Roll Roll Roll Roll Tube Lining, valve, packing, roll, hose,diaphragm, ◯ (square) ring, tube, sealing material Roll

TABLE 2 Field of Industry Characteristics Required Electrical Plasmaresistance, acid resistance, alkali resistance, amine resistance, ozoneresistance, gas resistance, chemical resistance, cleanliness, heatresistance Transportation Heat resistance, amine resistance Heatresistance, amine resistance Fuel resistance, fuel permeability, heatresistance Fuel resistance, fuel permeability, heat resistance Fuelresistance, fuel permeability, heat resistance Fuel resistance, fuelpermeability, heat resistance Chemical Chemical resistance, solventresistance, heat resistance, Chemical resistance, solvent resistance,heat resistance, Cleanliness Mechanical Chemical resistance Chemicalresistance Solvent resistance Solvent resistance Food Chemicalresistance, solvent resistance, heat resistance Metal Heat resistance,acid resistance

TABLE 3 Field of industry Parts Electrical ◯ ring and sealing materialfor gate valve of corresponding product or equipment ◯ ring and sealingmaterial for quartz window of corresponding product or equipment ◯ ringand sealing material for chamber of corresponding product or equipment ◯ring and sealing material for gate of corresponding product or equipment◯ ring and sealing material for bell jar of corresponding product orequipment ◯ ring and sealing material for coupling of correspondingproduct or equipment ◯ ring and sealing material for pump ofcorresponding product or equipment ◯ ring and sealing material for gascontroller for semiconductor of corresponding product or equipment ◯ring and sealing material for resist developing and releasing solutions◯ ring and sealing material for wafer cleaning solution Diaphragm ofpump for corresponding production equipment Hose for resist developingand releasing solutions Hose and tube for wafer cleaning solution Rollfor transferring wafer Lining and coating of tanks for resist developingand releasing solutions Lining and coating of tanks for wafer cleaningsolution Lining and coating of tanks for wet etching TransportationEngine head gasket Metal gasket Crank shaft seal Cam shaft seal Valvestem seal Manifold packing Oil hose ATF hose Injector ◯ ring Injectorpacking ◯ ring and diaphragm for fuel pump Fuel hose Chemical MechanicalDeveloping roll Developing roll Gravure roll Guide roll Gravure roll formagnetic tape production and coating line Guide roll for magnetic tapeproduction and coating line Various coating rolls Food Metal

The present invention is then explained based on examples andpreparation examples but is not limited to those examples.

PREPARATION EXAMPLE 1 Preparation of Fluorine-containing Multi-segmentPolymer Synthesis of Elastomeric Segment A

A 47-liter stainless steel autoclave having no ignition source wascharged with 30 liters of pure water, 300 g of C₇F₁₅COONH₄ as anemulsifying agent and 2.7 g of disodium hydrogenphosphate. 12H₂O as a pHcontrol agent, and after the inside of a system was sufficientlyreplaced with nitrogen gas, the autoclave was heated up to 50° C. withstirring at 200 rpm and a gas mixture of TFE and perfluoro(methyl vinylether) (PMVE) (32/68 in mole ratio) was introduced (780 g of a monomermixture) so that the inside pressure became 8.0 kgf/cm²G. Then 100 ml ofan aqueous solution of ammonium persulfate (APS) having a concentrationof 37.2 mg/ml was fed with pressurized nitrogen gas to initiate areaction.

At the time when the inside pressure lowered down to 7.0 kgf/cm ²G withadvance of the polymerization, 18.21 g of diiodine compound I(CF₂)₄I and234 g of an aqueous solution of 10% by weight of C₇F₁₅COONH₄ wereintroduced with pressurized nitrogen gas. Then 60 g of TFE was fed withself-pressure thereof and 58 g of PMVE was fed under pressure with aplunger pump (TFE/PMVE=63/37 in mole ratio) so that the pressure became8.0 kgf/cm²G. Thereafter TFE and PMVE were fed in the same manner underpressure with the advance of the reaction, and thus increasing andlowering of the pressure were repeated between 7 kgf/cm²G and 8kgf/cm²G.

When a total charging amount of TFE and PMVE reached 5,900 g twelvehours after starting of the polymerization reaction, the autoclave wascooled and un-reacted monomers were released to obtain an aqueousdispersion having a solid content of 16.0% by weight.

A part of the aqueous dispersion was sampled, frozen, coagulated andthawed, followed by washing a coagulated product with water and thenvacuum-drying to obtain a rubber-like polymer. A Mooney viscosity ML₁₊₁₀(140° C.) of the polymer was 58.

As a result of ¹⁹F-NMR analysis, monomer components of the polymer wereTFE/PMVE=61/39% by mole, and Tg (center value) measured according to DSCanalysis was 2° C.

Block Copolymerization with Non-elastomeric Segment B

The same 47-liter stainless steel autoclave as above was charged with3,200 g of the aqueous dispersion obtained above, 142 g ofperfluoro(propyl vinyl ether) (PPVE) and 400 g of pure water. Afterreplacing the inside of a system was sufficiently replaced with nitrogengas, the inside temperature was kept at 50° C. With stirring at 120 rpm,tetrafluoroethylene was introduced under pressure so that the insidepressure became 5.5 kgf/cm²G (amount of tetrafluoroethylene: 400 g).

Then a solution prepared by dissolving 0.4 g of ammonium persulfate in50 ml of water was introduced with pressurized nitrogen gas to initiatea reaction.

Since the inside pressure lowered down with the advance of thepolymerization reaction, at the time when it lowered to 5.0 kgf/cm²G, itwas again raised with a tetrafluoroethylene gas up to 5.5 kgf/cm²G, andthus increasing and lowering of the pressure were repeated.

At the time when 950 g of tetrafluoroethylene was consumed afterstarting of the polymerization, supplying thereof was stopped, theautoclave was cooled and un-reacted monomers were released to obtain6,000 g of a semi-transparent aqueous dispersion.

The polymer content of the obtained aqueous dispersion was 18.3% byweight, and the particle size thereof measured by dynamic lightscattering method was 58 nm.

The proportion of the non-elastomeric fluorine-containing polymer chainsegment B to the whole polymer which was calculated from an increase inyield of the polymer, namely, ((Yield of polymer obtained in postpolymerization)−(Amount of polymer charged))+(Yield of polymer obtainedin post polymerization)×100 was 17% by weight.

The obtained aqueous dispersion was frozen and coagulated, and theprecipitated polymer was washed and dried to obtain a white solid.

The white solid powder was charged in an electric oven maintained at230° C., and the inside of the oven was replaced with nitrogen gas,followed by flowing of 20% by volume of fluorine gas (nitrogen gas: 80%by volume) at a rate of 0.5 liter/min for five hours. After that, theinside of the oven was sufficiently replaced with nitrogen gas and theoven was cooled to obtain a fluorinated fluorine-containingmulti-segment polymer (white powder).

According to ¹⁹F-NMR analysis, components of the non-elastomericfluorine-containing polymer chain segment B in the obtainedfluorine-containing multi-segment polymer was TFE/PPVE=98/2% by mole.Also according to DSC analysis, the glass transition temperature of theelastomeric fluorine-containing polymer chain was 2° C. and thecrystalline melting point of the non-elastomeric fluorine-containingpolymer chain segment was 282° C. The melt flow rate measured underconditions of preheating at 372° C. for five minutes at a load of 5kgf/cm² by using Koka-type flow tester and nozzles of 2 mm diameter×8 mmlength was 4.9 g/10 min.

PREPARATION EXAMPLE 2 Preparation of Fluorine-containing Multi-segmentPolymer Synthesis of Elastomeric Segment A

A 47-liter stainless steel autoclave having no ignition source wascharged with 30 liters of pure water, 300 g of C₇F₁₅COONH₄ as anemulsifying agent and 2.7 g of disodium hydrogenphosphate.12H₂O as a pHcontrol agent, and after the inside of a system was sufficientlyreplaced with nitrogen gas, the autoclave was heated up to 50° C. withstirring at 200 rpm and a gas mixture of TFE/PMVE (32/68 in mole ratio)was introduced so that the inside pressure became 8.0 kgf/cm²G (monomermixture: 787 g). Then 100 ml of an aqueous solution of ammoniumpersulfate (APS) having a concentration of 68.6 mg/ml was fed withpressurized nitrogen gas to initiate a reaction.

At the time when the inside pressure lowered down to 7.0 kgf/cm²G withthe advance of the polymerization, 27.2 g of diiodine compound I(CF₂)₄Iand 234 g of an aqueous solution of 10% by weight of C₇F₁₅COONH₄ wereintroduced with pressurized nitrogen gas. Then 60 g of TFE was fed withself-pressure thereof and 58 g of PMVE was fed under pressure with aplunger pump (TFE/PMVE=63/37 in mole ratio) so that the pressure became8.0 kgf/cm²G. Thereafter TFE and PMVE were fed in the same manner underpressure with the advance of the reaction, and thus increasing andlowering of the pressure were repeated between 7 kgf/cm²G and 8 kgf/cm²G.

When the total charging amount of TFE and PMVE reached 6,000 g sixteenhours after starting of the polymerization reaction, the autoclave wascooled and un-reacted monomers were released to obtain an aqueousdispersion having the solid content of 16.6% by weight.

A part of the aqueous dispersion was sampled, frozen, coagulated andthawed, followed by washing a coagulated product with water and thenvacuum-drying to obtain a rubber-like polymer. The Mooney viscosityML₁₊₁₀ (100° C.) of the polymer was 59 and the Mooney viscosity ML₁₊₁₀(140° C.) of the polymer was 12.

As a result of ¹⁹F-NMR analysis, monomer components of the polymer wereTFE/PMVE=64/36% by mole, and Tg (center value) measured according to DSCanalysis was 3° C.

Block Copolymerization with Non-elastomeric Segment B

The same 47-liter stainless steel autoclave as above was charged with1,840 g of the aqueous dispersion obtained above, 208 g ofperfluoro(propyl vinyl ether) (PPVE) and 1,200 g of pure water. Afterthe inside of a system was sufficiently replaced with nitrogen gas, theinside temperature, was kept at 50° C. With stirring at 120 rpm,tetrafluoroethylene was introduced under pressure so that the insidepressure became 5.5 kgf/cm²G (amount of tetrafluoroethylene: 640 g).

Then the solution prepared by, dissolving 0.27 g of ammonium persulfatein 50 ml of water was introduced with pressurized nitrogen gas toinitiate a reaction.

Since the inside pressure lowered down with the advance of thepolymerization reaction, at the time when it lowered to 5.0 kgf/cm²G, itwas again raised with a tetrafluoroethylene gas up to 5.5 kgf/cm²G, andthus increasing and lowering of the pressure were repeated.

At the time when 1,400 g of tetrafluoroethylene was consumed afterstarting of the polymerization, supplying thereof was stopped, theautoclave was cooled and un-reacted monomers were released to obtain4,000 g of a semi-transparent aqueous dispersion.

The polymer content of the obtained aqueous dispersion was 21.0% byweight, and the particle size thereof measured by dynamic lightscattering method was 59 nm.

The proportion of the non-elastomeric fluorine-containing polymer chainsegment B to the whole polymer which was calculated from an increase inyield of the polymer, namely, ((Yield of polymer obtained in postpolymerization)−(Amount of polymer charged))+(Yield of polymer obtainedin post polymerization)×100 was 33% by weight.

The obtained aqueous dispersion was frozen and coagulated, and theprecipitated polymer was washed and dried to obtain a white solid.

The white solid powder was charged in an electric oven maintained at230° C., and the inside of the oven was replaced with nitrogen gas,followed by flowing of 20% by volume of fluorine gas (nitrogen gas: 80%by volume) at a rate of 0.5 liter/min for five hours. After that, theinside of the oven was replaced with nitrogen gas sufficiently and theoven was cooled to obtain a fluorinated fluorine-containingmulti-segment polymer (white powder).

According to ¹⁹F-NMR analysis, components of the non-elastomericfluorine-containing polymer chain segment in the obtainedfluorine-containing multi-segment polymer was TFE/PPVE=98/2% by mole.Also according to DSC analysis, the glass transition temperature of theelastomeric fluorine-containing polymer chain was 3° C. and thecrystalline melting point of the non-elastomeric fluorine-containingpolymer chain segment was 297° C. The melt flow rate measured underconditions of preheating at 372° C. for five minutes at a load of 5kgf/cm² by using Koka-type flow tester and nozzles of 2 mm diameter×8 mmlength was 3.5 g/10 min.

EXAMPLE 1

The white solid of fluorine-containing multi-segment polymer prepared inPreparation Example 1 and PFA (NEOFLON PFA AP201 available from DAIKININDUSTRIES, LTD. and having a crystalline melting point of 302° C.) weredry-blended in a weight ratio of 80/20 and kneaded at 350° C. with atwo-screw extruder (LABOPLASTOMILL available from TOYO SEIKI KABUSHIKIKAISHA), followed by extruding to obtain a flexible fluorine-containingmaterial of the present invention in the form of pellets.

The obtained pellets were put in a 100 mm diameter metal die which wasthen set on a press machine set at 350° C., followed by preheating for30 minutes and then compression-molding at 70 kg/cm² for one minute toobtain an about 0.5 mm thick film.

The following physical properties of the obtained film were measured.The results are shown in Table 4.

(Mechanical Properties)

Tensile strength: The film is cut to a form of dumbbell described inASTM-1467, and measurements are carried out at a cross head speed of 200mm/min by using a TENSILON universal tester available from OrientecCorporation.

Elastic modulus: The film is cut to a form of dumbbell described inASTM-1467, and measurements are carried out at a cross head speed of 200mm/min by using a TENSILON universal tester available from OrientecCorporation.

Rubber hardness: Hardness A is measured according to JIS K 6301.

Resin hardness: Hardness D is measured according to JIS K 7215.

(Viscoelasticity)

The film is cut to a form Of strip of about 35×5 mm and set on aviscoelasticity meter RSA-2 available from Rheometric Co., Ltd. Then aviscoelasticity is measured at a frequency of 1 Hz at 150° C. and 200°C.

(Mold-processability)

A melt flow rate is measured under conditions of preheating at 372° C.for five minutes at a load of 5 kgf/cm² by using Koka-type flow tester(CFR-500C available from Shimadzu Corporation) and nozzles of 2 mmdiameter×8 mm length.

(Surface Characteristics)

Water contact angle: A water contact angle on the film surface ismeasured at room temperature by using a contact angle meter.

Contact angle of 31 dyne solution: A solution (31 dyne solution) havinga surface tension of 31 dyne/cm is prepared by mixing 97.5 (v/v %) ofethylene glycol and 2.5 (v/v %) of formaldehyde. A contact angle of 31dyne solution is measured by using a contact angle meter.

(Non-tackiness)

Tackiness: The same two films are overlapped with each other and pressedat a load of 10 kgf for one minute. Then the films are separated.Tackiness is evaluated by a feeling of stickiness at separating.Criteria for judgement are represented by ⊚ when the films are separatedspontaneously when the load is released; ∘ when the films can beseparated and peeled off by hands; and× when the films cannot beseparated or are broken when peeled off.

Stain-proofing property: Five lines of 3 cm long are drawn on the filmwith a commercially available oily ink (black), and after air-drying for60 seconds, the surface of the film is rubbed by ten turns with a 500 gmetallic disc (50 mm diameter) with a commercially available gauze stuckon a flat bottom surface thereof. The evaluation is indicated by× whenthe lines remain un-erased after the rubbing by ten turns and ∘ when nolines remain.

EXAMPLES 2 to 3

A flexible fluorine-containing material of the present invention wasproduced in the same manner as in Example 1 except that the mixing ratioof the fluorine-containing multi-segment polymer (a) to PFA (b) waschanged as shown in Table 4, and each physical property was evaluated inthe same manner as in Example 1. The results are shown in Table 4.

EXAMPLE 4

A flexible fluorine-containing material of the present invention wasproduced in the same manner as in Example 1 except that the polymerprepared in Preparation Example 2 was used as the fluorine-containingmulti-segment polymer (a), and each physical property was evaluated inthe same manner as in Example 1. The results are shown in Table 4.

EXAMPLE 5

A flexible fluorine-containing material of the present invention wasproduced in the same manner as in Example 2 except that FEP (NEOFLON FEPNP20 available from DAIKIN INDUSTRIES, LTD.) was used as thefluorine-containing resin (b) instead of PFA, and a film was produced.Each physical property was evaluated in the same manner as in Example 1.The results are shown in Table 4.

TABLE 4 Ex. 1 Ex. 2 Ex. 3 Ex. 4 Ex. 5 Fluorine-containing materialFluorine-containing multi-segment polymer (a) Elastomeric TFE/ TFE/ TFE/TFE/ TFE/ segment A PMVE PMVE PMVE PMVE PMVE (% by mole) (61/39) (61/39)(61/39) (64/36) (61/39) Non-elastomeric TFE/ TFE/ TFE/ TFE/ TFE/ segmentB PPVE PPVE PPVE PPVE PPVE (% by mole) (98/2)  (98/2)  (98/2)  (98/2) (98/2)  Proportion of B in (a) 17 17 17 33 17 (% by weight)Fluorine-containing PFA PFA PFA PFA FEP resin (b) (a)/(b) (weight ratio)80/20 60/40 20/80 80/20 60/40 Properties of material Mechanicalproperties Tensile strength 101 118 173 112 105 (kg/cm²) Elastic modulus152 189 212 168 145 (kg/cm²) Rubber hardness 54 64 85 58 59 (ASTR-A)Resin hardness 22 25 44 23 23 Viscoelasticity 150° C.-E′ 6.50 6.70 6.806.55 6.2 (107 dyn/cm²) 200° C.-E′ 4.10 5.80 5.60 4.30 3.9 (107 dyn/cm²)Mold-processability 5.5 7.9 11.9 4.1 6.8 (MFI: 372° C., 5 kgf) Surfacecharacteristics Water contact angle 110 114 112 112 113 (degree) Contactangle of 31 58 61 57 59 60 dyne solution (degree) Non-tackinessTackiness ◯ ◯ ◯ ◯ ◯ Stain-proofing ◯ ◯ ◯ ◯ ◯ property

COMPARATIVE EXAMPLE 1

A fluorine-containing material for comparison was produced in the samemanner as in Example 1 except that PFA was not mixed, and each physicalproperty was evaluated in the same manner as in Example 1. The resultsare shown in Table 5.

COMPARATIVE EXAMPLE 2

A fluorine-containing material for comparison was produced in the samemanner as in Example 4 except that PFA was not mixed, and each physicalproperty was evaluated in the same manner as in Example 1. The resultsare shown in Table 5.

COMPARATIVE EXAMPLE 3

A film was produced in the same manner as in Example 1 except that PFA(same one as in Example 1) was used alone without using afluorine-containing multi-segment polymer, and each physical propertywas evaluated in the same manner as in Example 1. The results are shownin Table 5.

COMPARATIVE EXAMPLE 4

A fluorine-containing material for comparison was produced in the samemanner as in Example 1 except that 67 parts by weight of a polymerprepared by fluorinating, in the same manner as in Preparation Example1, the elastomeric polymer (a polymer before copolymerizing anon-elastomeric segment, TFE/PMVE=61/39 (mole ratio)) prepared inPreparation Example 1 and 33 parts by weight of PFA were used, and eachphysical property was evaluated in the same manner as in Example 1. Theresults are shown in Table 5.

TABLE 5 Com. Com. Com. Com. Ex. 1 Ex. 2 Ex. 3 Ex. 4 Fluorine-containingmaterial Fluorine-containing multi-segment polymer (a) Elastomericsegment A TFE/ TFE/ — TFE/ PMVE PMVE PMVE (% by mole) (61/39) (64/36) —(61/39) Non-elastomeric TFE/ TFE/ — — segment B PPVE PPVE — — (% bymole) (98/2)  (98/2)  Proportion of B in (a) 17 33 — 0 (% by weight)Fluorine-containing — — PFA PFA resin (b) (a)/(b)(weight ratio) 100/0 100/0   0/100 67/23 Properties of material Mechanical properties Tensilestrength (kg/cm²) 77 95 277 35 Elastic modulus (kg/cm²) 49 143 420 240Rubber hardness (ASTR-A) 48 56 >95 74 Resin hardness 20 23 60 40Viscoelasticity 150° C.-E′ 3.10 6.50 88.0 2.80 (107 dyn/cm²) 200° C.-E′1.20 4.60 48.0 0.35 (107 dyn/cm²) Mold-processability 4.9 3.5 18.6 15(MFI: 372° C., 5 kgf) Surface characteristics Water contact angle(degree) 106 108 110 98 Contact angle of 31 dyne 53 55 55 51 solution(degree) Non-tackiness Tackiness x x ⊚ x Stain-proofing property x x ∘ x

INDUSTRIAL APPLICABILITY

As it is clear from the results of Table 4 and 5, in case where thefluorine-containing resin (PFA) is not mixed (Comparative Examples 1 and2), non-tackiness (particularly stain removability) is inferior, and incase of a sole use of the fluorine-containing resin (PFA) (ComparativeExample 3), the material does not have a flexibility at all. Also incase of the mixture comprising PFA and the fluorine-containing polymerwhich is not copolymerized with the non-elastomeric segment (ComparativeExample 4), not only a mechanical strength is inferior but alsomechanical properties are suddenly lowered at high temperature andnon-tackiness is inferior. On the other hand, the flexiblefluorine-containing material of the present invention can providevarious products, particularly products and parts for OA equipment whichare excellent in flexibility, mechanical strength, viscoelasticity (heatresistance) and mold-processability and have improved non-tackiness(particularly stain removability).

What is claimed is:
 1. A flexible fluorine-containing material whichcomprises (a) a fluorine-containing multi-segment polymer having anelastomeric fluorine-containing polymer chain, segment A and anon-elastomeric fluorine-containing polymer chain segment B in which theelastomeric fluorine-containing polymer chain segment A comprises notless than 90% by mole of a perhaloolefin unit and (b) afluorine-containing resin having a crystalline melting point or glasstransition temperature of not less than 150° C., in which a weight ratio(a)/(b) is 1/99 to 99/1.
 2. The flexible fluorine-containing material ofclaim 1, wherein said fluorine-containing resin (b) has a crystallinemelting point or glass transition temperature of not less than 250° C.3. The flexible fluorine-containing materials of claim 1, wherein saidweight ratio (a) (b) is 20 80 to 99
 1. 4. The flexiblefluorine-containing material of claim 1, wherein the elastomericfluorine-containing polymer chain segment A contained in thefluorine-containing multi-segment polymer (a) is non-crystalline and hasa glass transition temperature of not more than 25° C.
 5. The flexiblefluorine-containing material of claim 4, wherein the non-elastomericfluorine-containing polymer chain segment B contained in thefluorine-containing multi-segment polymer (a) is a polymer chain havinga crystalline melting point or glass transition temperature of not lessthan 150° C.
 6. The flexible fluorine-containing material of claim 1,wherein the non-elastomeric fluorine-containing polymer chain segment Bcontained in the fluorine-containing multi-segment polymer (a) is apolymer chain having a crystalline melting point or glass transitiontemperature of not less than 150° C.
 7. The flexible fluorine-containingmaterial of claim 6, wherein the non-elastomeric fluorine-containingpolymer chain segment B contained in the fluorine-containingmulti-segment polymer (a) is a polymer chain having a crystallinemelting point or glass transition temperature of not less than 250° C.8. The flexible fluorine-containing material of claim 1, wherein theelastomeric fluorine-containing polymer chain segment A contained in thefluorine-containing multi-segment polymer (a) is a polymer chain having50 to 85% by mole of tetrafluoroethylene and 15 to 50% by mole ofperfluoro(alkyl vinylether) and or hexafluoropropylene.
 9. The flexiblefluorine-containing material of claim 8, wherein the non-elastomericfluorine-containing polymer chain segment B contained in thefluorine-containing multi-segment polymer (a) is a polymer chaincomprising more than 85% by mole and not more than 100% by mole oftetrafluoroethylene and 0% by mole or less than 15% by mole of acompound of the formula (1): CH₂═CF—R_(f) ¹  (b 1) wherein R_(f) ¹ CF₃or OR_(f) ¹ in which R_(f) ² is a perfluoroalkyl group having 1 to 5carbon atoms.
 10. The flexible fluorine-containing material of claim 9,wherein the fluorine-containing resin (b) is one or more member selectedfrom perfluoro fluorine-containing resins.
 11. The flexiblefluorine-containing material of claim 1, wherein the non-elastomericfluorine-containing polymer chain segment B contained in thefluorine-containing multi-segment polymer (a) is a polymer chaincomprising more than 85% by mole and not more than 100% by mole oftetrafluoroethylene and 0% by mole or less than 15% by mole of acompound of the formula (1): CF₂═CF—R_(f) ¹  (1) wherein R_(f) ¹is CF₃OR_(f) ² is a perfluoroalkyl group having 1 to 5 carbon atoms.
 12. Theflexible fluorine-containing material of the claim 1, wherein thefluorine-containing resin (b) is one or more members selected fromperfluoro fluorine-containing resins.
 13. The flexiblefluorine-containing material of claim 12, wherein thefluorine-containing resin (b) is one or more members selected frompolytetrafluoroethylene, tetrafluoroethylene/perfluoro(alkyl vinylether) copolymer, tetrafluoroethylene/hexafluoropropylene copolymer andtetrafluoroethylene/hexafluoropropylene/perfluoro(alkyl vinyl ether)copolymer.
 14. The flexible-containing material of claim 1, wherein aproportion of the non-elastomeric fluorine-containing polymer chainsegment B contained in the fluorine-containing multi-segment polymer (a)is not more than 25% by weight based on the whole segment polymer (a).